TITLE "LIQUID TRANSPORT VESSEL" FIELD OF THE INVENTION
The present invention relates a vessel for transporting liquids. BACKGROUND OF THE INVENTION
It is common for vehicles transporting liquids, such as fuel tankers, to use the vessels on the vehicle for different types of liquids. In most cases, if a vessel is to be used for a type of liquid which differs from what has been used previously in the vessel, the vessel must be cleaned first.
As an example, it common for single tanker to transport crude oil to a particular location and then return filled with diesel fuel. Before the vessels on the tanker can be filled with diesel, the vessels need to be cleaned to avoid contamination. The cleaning of the vessel adds to the total transport costs and also increases the time taken for the trip.
The present invention attempts to overcome at least in part the aforementioned disadvantages of previous transport vessels used for transporting different liquids.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention there is provided a transport vessel characterised by comprising a first inlet, a second inlet and a flexible bladder contained within the vessel, wherein the first inlet is in fluid communication with the interior of the vessel and the second inlet is in fluid communication with the flexible bladder, such that liquid entering the first inlet fills the space within the vessel around the bladder and liquid entering the second inlet fills the flexible bladder. DESCRIPTION OF THE DRAWINGS
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side cross sectional view of a liquid transport vessel in accordance with the present invention;
Figure 2 is a side view of a tanker comprised of three of the liquid transport vessels of
Figure 1;
Figure 3 is a top view of the tanker of Figure 2 with the top of the vessel and the bladder removed;
Figure 4a is an end cross sectional view of the liquid transport vessel of Figure 1 during the filling of the flexible bladder; and
Figure 4b is an end cross sectional view of the liquid transport vessel of Figure 1 during the filling of the space around the flexible bladder. DESCRIPTION OF THE INVENTION
Referring to the Figures, there is shown a liquid transport vessel 10 generally of the type used on conventional tankers. The vessel 10 is generally cylindrical in shape and includes a first inlet 12 and a second inlet 14. The vessel 10 also includes a flexible bladder 16 arranged within the vessel 10. The flexible bladder 16 is constructed of a material that is suitably resistant to the types of liquids to be transported by the liquid transport vessel 10. The flexible bladder 16 is of a size such that it completely fills space within the vessel 10 when the flexible bladder 16 is filled with liquid. The first inlet 12 is in fluid communication with the space within the vessel 10 around the flexible bladder 16. The second inlet 14 is in fluid communication with the interior of the flexible bladder 16. The first and second inlets 12 and 14 are provided on the upper surface of the vessel 10. Also provided are first and second outlets 22 and 24 on the lower surface of the vessel 10. The first outlet 22 is in fluid communication with the space within the vessel 10 around the flexible bladder 16. The second outlet 22 is in fluid communication with the interior of the flexible bladder 16. The flexible bladder 16 is suspended along its length from one or more upper rails 18 provided within the vessel 10. In the embodiment shown in the Figures, there is provided a first upper rail 30 and a second upper rail 32. The first and second upper rails 30 and 32 are arranged generally parallel to each other on either side of the first and second inlets 12 and 14. In order to support the first and second upper rails 30 and 32, the upper interior surface of the vessel 10 is provided with a first set of securing rings 34 and a second set of securing rings 36. The first set of securing rings is provided in a line along the length of the vessel 10 such that the first upper rail 30 is passed through the first set of securing rings 34 and thereby supported from the upper inner surface of the vessel 10. The second set of securing rings 36 is provided in a line along the length of the vessel 10 generally parallel to the first set of securing rings 34 such that the second upper rail 32 is passed through the second set of securing rings 36 and thereby supported from the upper inner surface of the vessel 10. The upper surface of the flexible bladder 16 is provided with a plurality of flexible loops along it length. The flexible loops are provided as a first set of flexible loops arranged such that the first upper rail 30 is received within each of the first set of flexible loops, thereby supporting the flexible bladder 16 from the first upper rail 30.
Also provided is a second first set of flexible loops arranged such that the second upper rail 32 is received within each of the second set of flexible loops, thereby supporting the flexible bladder 16 from the second upper rail 30. Preferably the flexible loops are provided extending along each of the first and second upper rails 30 and 32 between each adjacent pairs of securing rings.
Further, one or more lower rails 20 are provided extending longitudinally along the lower interior surface of the vessel 10. In the embodiment shown in the Figures, there is provided first and second lower rails 40 and 42. The first and second lower rails 40 and 42 are arranged generally parallel to each other on either side of the first and second outlets 22 and 24. In order to secure the first and second lower rails 40 and 42, the lower interior surface of the vessel 10 is provided with a third set of securing rings 44 and a fourth set of securing rings 46. The third set of securing rings is provided in a line along the length of the vessel 10 such that the first lower rail 40 is passed through the first set of securing rings 34 and thereby secured to the lower inner surface of the vessel 10. The fourth set of securing rings 46 is provided in a line along the length of the vessel 10 generally parallel to the third set of securing rings 44 such that the second lower rail 42 is passed through the fourth set of securing rings 46 and thereby secured to the lower inner surface of the vessel 10. The lower surface of the flexible bladder 16 is provided with third and fourth sets of flexible loops to secure to the third and fourth lower rails 40 and 42 in the same manner as to the upper rails 18.
Preferably the distance between the first and second upper rails 30 and 32 is greater than the distance between the first and second lower rails 40 and 42, as shown in Figure 4. Also, the distance around the inner surface of the vessel 10 from the first or second upper rail 30 or 32 to the respective first or second lower rail 40 or 42 is less than the distance from the first or second upper rail 30 or 32 horizontally across to a vertical centre line of the vessel 10, down the vertical centre line and horizontally out to the respective first or second lower rail 40 or 42. In this way, when liquid is supplied into the vessel 10 around the flexible bladder 16, the flexible bladder 16 is compressed to hang generally vertically down the centre of the vessel 10 with no stress on the flexible bladder 16. The vessel 10 is also provided with a barrier member 50 adjacent the first outlet 22, as shown in Figure 1. The barrier member 50 is provided to allow liquid from within the vessel 10 to flow to the first outlet 22 but to restrain the flexible bladder 50 from moving across and blocking the first outlet 22. In use, the vessel 10 is filled with a first liquid via the first inlet 12. The first liquid fills the space within the vessel 10 around the flexible bladder 16. The flexible bladder 16 is compressed flat such that sides of the flexible bladder come together along the centre of the vessel 10 as shown in Figure 4b. The air within the flexible bladder 16 is expelled through the second inlet 14. Following transportation of the first liquid, the first liquid is removed from the vessel 10 via the first outlet 22. When it is required to fill the vessel 10 with a second liquids being different from the first liquid, the flexible bladder 16 is inflated by means of compressed air injected through the second inlet 14. The inflating of the flexible bladder 16 removes any bunching up of the flexible bladder material on the floor of the vessel 10 which would cause stretching of the flexible bladder 16 during filling. Alternatively, the flexible bladder 16 may be inflated by using a vacuum pump to decrease the pressure around the bladder. This arrangement has the advantage that no pressure differential is created between the inside of the bladder 16 and any hose or fill attachment.
As a further alternative, the bladder may expanded during the emptying of the vessel
10 by allowing only venting of the bladder 16 and not the space around the bladder 16. Removing liquid from the space within the vessel around the bladder 16 thereby causes the bladder to inflate due to the pressure differential. The same process can be used to compress the bladder 16 during emptying of the bladder to the correct position by venting only the space around the bladder 16.
The vessel 10 is then filled with the second liquid via the second inlet 14. The suspension of the flexible bladder 16 between the upper and lower rails 18 and 20 maintains the flexible bladder 16 in the correct position. Following transport of the second liquid, the second liquid may be removed from the vessel 10 via the second outlet 24.
It will be appreciated that while the vessel 10 has been described as having inlets at the top and outlets at the bottom, the outlets could also be used for filling in a bottom filling operation. That is, the first and second outlets 22 and 24 would act as both inlets and outlets. In this case, the upper inlets 12 and 14 could be retained as alternate inlets and for venting.
Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention